The number of echoes combined into a single image or image set in multiple echo imaging sequences or echo-train techniques such as rapid acquisition with relaxation enhancement (RARE), fast-spin echo (FSE), and turbo spin-echo (TSE). In RARE imaging, the ETL typically equals the acceleration factor.
As for tooth pain, it is caused by a reaction of the nerves inside a tooth's pulp chamber with the severity dependent upon the type and degree of the stimulus. What follows are some examples of symptoms you may be feeling and their possible causes.
Teeth sensitivity or when your teeth hurt means that you have dentin hypersensitivity. This is due to cold factors affecting your teeth: eating of cold food, drinking of cold liquid beverages and cold air conditioner or cold air.If this condition gets to be prolonged or if the pain is truly excruciating, then, this is a symptom of unhealthy teeth and the nerve that goes with it.The condition starts when the gums recede or ebb. The gums protect the roots of the teeth like a blanket covering a child from the cold.hese roots have tubules or the tubes that are connected to the nerves of the tooth. Tooth ache or pain is being activated when there is pressure or cold stimuli. This happens because the roots are open and bare. If it was not, then, there would be no pain since the root is being enveloped by the gums.